The invention herein resides in the art of automotive vehicles and, more particularly, of the type driven by a fuel powered engine. Specifically, the invention relates to a fuel tank for receiving and maintaining compressed natural gas as the fuel for such a vehicle.
Modern transportation requires the extensive use of over-the-road vehicles such as automobiles, vans, trucks, and the like. Presently, such vehicles are powered by an engine which is fueled by gasoline or diesel fuel. The use of such fuels has given rise to two apparent shortcomings. First, such fuels are in limited supply throughout the world and the international control of such fuels causes their price and availability to be uncertain. A second shortcoming of such fuels is their adverse impact on the environment. It is generally believed that the hydrocarbon gases released from the combustion of gasoline or diesel fuel in an internal combustion engine is environmentally undesirable.
It is known that natural gas is in bountiful supply in the United States and that the burning of such gas is environmentally compatible. It is also known that internal combustion engines can operate efficiently on natural gas. However, the use of natural gas as a vehicle fuel has been constrained by the xe2x80x9crangexe2x80x9d afforded the vehicle using such fuel. In the past, tanks of compressed natural gas have been placed in the trunk or other cargo carrying areas of the vehicle and interconnected with the fuel system for passage to fuel injectors or the like. However, the availability of storage areas in vehicles suitable for receiving such tanks of compressed natural gas is somewhat limited and such limitation necessarily constrains the distance that the vehicle can travel without refueling. Accordingly, the range of vehicles employing natural gas fuel has necessarily been significantly limited in the past.
The prior art has been substantially devoid of the presentation of a vehicle having an internal combustion engine and having fuel tanks provided as an integral portion of the vehicle to serve for holding natural gas fuel for use by the engine. The requirement that the natural gas be introduced into the fuel tanks at high levels of pressure have typically dictated that the tanks be specially designed for simple retention in storage areas of the vehicle, and the prior art has not envisioned a manner for incorporating fuel tanks as a structural portion of the vehicle itself. Indeed, fuel tanks of sufficient strength to receive and maintain large volumes of natural gas at high pressure levels while serving as a structural element of the vehicle are not known. Indeed, the prior art has envisioned the use of natural gas as the fuel for vehicles as being more of a novelty feature for use by vehicle fleets serving a limited area, rather than as a practical means for avoiding the shortcomings inherent in the use of gasoline and diesel fuels.
In the above referenced copending application Ser. No. 08/062,279, filed May 17, 1993, a single steel tank of rectangular construction was presented. That concept is set forth in FIGS. 1-5, herein. While such a tank assembly is quite suitable for its intended purposes, its rectangular configuration dictates substantial wall thickness to maintain the contemplated pressures. Such results in unnecessary cost and weight for the tank assembly and vehicle as a whole.
In light of the foregoing, it is a first aspect of the invention to provide a compressed natural gas fuel tank for vehicles providing significantly extended capacity over prior art tanks.
Another aspect of the invention is the provision of a compressed natural gas fuel tank for vehicles in which the tank is formed as an integral and structural element of the vehicle frame.
Yet another aspect of the invention is the provision of a compressed natural gas fuel tank for vehicles which is capable of receiving and maintaining large volumes of natural gas at high pressure levels.
Still a further aspect of the invention is the provision of a compressed natural gas fuel tank for vehicles which can be positioned and maintained beneath the vehicle, in an unobtrusive and safe manner.
Still a further aspect of the invention is the provision of a compressed natural gas fuel tank for vehicles which is easy to construct and conducive to implementation with presently existing vehicles by retrofitting the same, and to new vehicles as a new assembly.
An additional aspect of the invention is to provide a compressed natural gas fuel tank for vehicles wherein a plurality of high pressure tanks are maintained within a tank housing which forms an integral and structural element of the vehicle frame.
Still a further aspect of the invention is to provide a compressed natural gas fuel tank for vehicles wherein a plurality of high pressure tanks are interconnected with a common manifold and maintained within a tank housing forming a structural element of the vehicle frame.
Another aspect of the invention is the provision of a compressed natural gas fuel tank for vehicles wherein a plurality of high pressure tanks constructed of composite material may be received in a tank housing forming a portion of the vehicle frame, and wherein a weight savings is realized over such a fuel tank formed of rectangular steel construction.
The foregoing and other aspects of the invention which will become apparent as the detailed description proceeds are achieved by a compressed natural gas fuel tank assembly for a vehicle, comprising: a tank housing having a plurality of cylindrical pressure tanks therein; first means extending from said tank housing for engaging a side rail of the vehicle; and second means interengaging said tank housing and a floor of the vehicle for securing said tank housing to said floor.
Other aspect of the invention which will become apparent herein are achieved by a compressed gas fuel tank assembly for a vehicle, comprising: a tank housing positioned within a discontinuity in a side rail of a frame of a vehicle, said tank housing maintaining a plurality of pressure tanks therein; channel members extending from opposite ends of the tank housing and being securedly engaged to respective ends of said side rail on opposite sides of said discontinuity; and means securing said tank housing to a floor of the vehicle.